Objective: To investigate the role of cortisol effects on RNA synthesis and metabolism in the mechanisms of glucocorticoid-induced dissolution of malignant lymphocytes. Approach: Corticoid-sensitive tumor (P1798) lymphocytes will be incubated with cortisol for varying periods of time and labeled with radioactive uridine or adenosine. RNA will be phenol extracted and fractionated by agarose-polyacrylamide gel electrophoresis or by chromatography on columns of poly(u)-Sepharose 4B. Profiles will be compared with those obtained, using RNA from control cells not treated with cortisol.